Fire control gyroscopes



FIRE CONTROL GYBGS COPES Filed May 23. 1951 2 Sheets-Sheet 1 Aug. 30, 1966 E. LEEDS FIRE CONTROL GYROSCOPES 2 Sheets-Sheet 2 Filed May 25 1951 INVENTOR Bava/wmf A L 550.5 BY

ATTORNEY.

United States Patent O 3,2d9,196 FIRE CONTRUL GYRGStPlES Benjamin L. Leeds, Huntington Station, NE., assignor, by mesne assignments, to the United States ot America as represented by the Secretary of the Army Filed May 23, 1951, Ser. No. 227,840 Claims. (Cl. i4- 5.4)

This invention relates to lire control devices and computers concerned with the proper aiming of missiles at high speed targets. More particularly, it relates to improvements in the construction of gyroscopes used in such devices, not only for stabilizing the gun and sight, but also for introducing the proper ballistic corrections. As disclosed in the prior patents of Garbarini and Wing, No. 2,423,831, dated July 15, 1947, for Apparatus for Directing Guns; and Wong, No. 2,504,170, dated April 18, 1950 for Gyroscope Processing Mechanism, a gyroscope. of the three degree of freedom type has been employed for such purposes, the position of the gyroscope being controlled by calculated torques about its axes to cause the gun to follow the target in azimuth and elevation with the calculated corrections applied between the gun and the sight. Such gyroscopes have become known in the art as angle gyroscopes, since they do not remain fixed 'but are caused to precess at a desired rate by applying a calculated torque suncient to cause such precession at such a rate. Such gyroscopes remain unaffected, however, by rolling, pitching and yawing of the craft on which they are mounted and hence also stabilize the sight and gun on the target. By measuring the torque applied, the angular rate of the target movement is determined as a scalar quantity.

In the prior art such as described in the above patents, coil springs have been employed to apply the torques, the stretched length of the spring being varied in proportion to the stiffness desired. Such devices, however, do not always give the desired accuracy because of Variations in the spring coefiicients under different degrees of stretching. Also, the prior art devices are inaccurate when the gyroscope changes position about the axis about which the torque is being applied. By my invention, I overcome the above defects and shortcomings of the prior art by devising means for varying the applied torque without changing the length or tension of the spring, by varying the length of the springs effective lever arm about the pivotal axis. I have also devised a mechanism in which the torque applied to the gyro by the spring remains substantially unaffected even when the position of the gyro about the torque axis may change through normal lag angles.

Referring to the drawings showing one form my invention may assume,

FIG. l is a diagrammatic view in perspective of an angle gyroscope and its controls constructed according to my invention;

FIG. 2 is a diagram illustrating my improved spring and lever arrangement for exerting controlled torques on the gyro, the levers being in the normal or zero position;

FIG. 3 shows a characteristic position assumed by the levers of FIG. 2 when a torque is being applied to the gyro;

FIG. 4 shows the position of the levers in the zero position when the gyro with its connected bar has moved through a small angle from its normal position about its torque axis; and

FIG. 5 shows a characteristic position of the parts when torque is applied to the gyro under lsuch conditions.

The type of tire control mechanism to which my invention more particularly applies is shown in the aforesaid patents of Wong and Garbarini et al., and it will be understood that the invention may be used on either a "ice radar sighting system or an optical sighting system, although only the latter is illustrated. In such systems, the sight and gun are controlled and stabilized in both azimuth and elevation from a gyroscope 1, to which controlled torques are applied indirectly, from handle bars or other controllers (not shown), the motions of which feed into a computing device or ballistic computer (not shown) controlling suitable azimuth and elevation transmitters or potentiometers 2 and 4, the former controlling the sight in azimuth and the latter in elevation. For this purpose, each potentiometer is shown as feeding into a precession servo motor amplifier 6, (6'), which controls a motor 8, (3'), operating a pinion lil through a train of gears 9. If desired, a feedback potentiometer 13 may be provided, actuated from some point in the gear train 9.

Pinion 10 when turned displaces a rack bar 12 to and fro which rotates a plate or lever 14 about its horizontal pivot 1d through a pin and fork connection 32, 33. Pivoted on the plate 14 at 18 is bell crank lever 2U with its acute angle faced away from pivot 16. To one end of the bell crank is connected a link 22 extending to a point on the gyroscope remote from the axis 3d thereof about which torque is applied. As shown, the link 22 is actually connected to one end of the stabilized bar 24 connected to an H-shaped frame 34 pivoted on vertical trunnions 29 on the rotor casing 26 of the gyroscope 1. A spring 25 connects the other end of the bell crank to a in 27 on plate 14 adjacent pivot 16. Bar 24 and framework 34- are also pivoted on fixed axis 2S Vwhich is normally in line with the horizontal tilt axis 30 of the gyroscope, as hereinafter described.

It should be noted also that the point of connection 21 of link 22 to the bell crank Ztl is also normally in line with axis 28 and with the pin 32 on plate 14 which is engaged by the fork 33 of rack bar 12. (FIG. 2). Spring 25 is normally placed under the proper tension when the parts are in the position shown in FIGS. 1 and 2, but in this position, it will be noted that -notorque is exerted on the bar or gyro because although the spring is extended, the pull on the bell crank lever about its pivot 13 will exert no torque on bar 24 through link 22 as long as the pins 21 and 23 connecting link 22 to the bell crank 20 and bar 24 are in line with axis 28 and bar 24. If, however, the plate 14 is moved to the right in FIG. 2., the parts lwill assume the position shown in FIG. 3. In this position, it will be observed that the spring 25 will exert through the bell crank lever 20l and link 22, a torque on the bar and gyro tending to rotate it counterclockwise as shown in FIG. 3. At the same time, the length of the spring is not varied and the force exerted on the bar 24, i.e., on the gyro, will be a linear function of the displacement of the rack 12.

It should be remembered that any force exerted about the horizontal axis 30 of the gyro does not cause precession about such axis, but, on the other had, causes precessional orientation of the gyro in azimuth. A similar spring mechanism (with primed reference characters) is provided about the vertical axis to cause precession of the gyro in elevation. It may be, therefore, the two devices are operating at the same time, in which case the bars 24 and 24 would be moved with the gyroscope.

The gyroscope is shown as having a vertical ring 32 mounted for orientation and which supports the gyro casing 26 for freedom about a horizontal axis 30 through an auxiliary gimbal ring 40 which also piv'otally mounts the casing about an axis 45 coincident with the spin axis of the rotor (not shown). The bar 24 is shown as secured to the H-shaped framework, pivoted on top and bottom of the case so as to tilt therewith about axis 28, 28'. Said framework at the outer end normally supports through pivots 36, 36 a prism 38 for directing the optics. Tilting of the framework 34 may be limited by xed stops 40. The prism is orientated from the gyroscope by means of a belt 42 and pulleys 44 and 46, so that the prism is turned through half the angle that the gyro turns with respect to the system. The line of sight is represented by the line 48 leading from the eye through the lens 30 and through reflecting prism 38 toward the target T.

In case the gyro has moved from its normal position, as stated, bar 24 may assume the inclined position shown in FIG. 4. In this position it will be observed that the spring 25 is still exerting no effective torque on the bar, since the link 22 is still in line with bar 24 and its pivot point 28 and member 14 has not moved. If now the rack bar 12 is moved so as to displace the plate 14 as in FIG. 3, the parts will then assume the position shown in FIG. 5. In this position, it will be seen, bell crank 20 has been given a slight clockwise rotation so that the spring 25 is slightly shortened. However, it should be observed, on the other hand, that the effective lever arm of the spring on the bell crank lever, namely, the distance L' in FIG. 5, as compared to the corresponding distance L in FIG. 3, has been increased slightly. At the same time, lever arm N in FIG. also becomes slightly shorter than lever arm N in FIG. 3. With the proper design of the bell crank angles and spring coefficient, this increase in the lever advantage may be made to closely balance the decrease in spring tension, so that the torque exerted through the link 22 on the bar 24 remains unchanged as compared to the torque exerted in FIG. 3, so that approximately the same torque will be exerted on the gyro upon a predetermined displacement of the fork 33 on rack 12 whether the gyro is in its normal position about its axis or somewhat displaced therefrom. It will be understood that the same action takes place around the vertical axis since the linkage system is identical.

The controllers at the gyro are shown as inductive pick-offs 46 and 46', the former being located adjacent the upper end of the bar 24 to which the armature 48 is secured. A similar armature 48 is mounted on the cor- -responding horizontal bar 24 about the vertical axis which cooperates with the pick-01T inductive device 46' to generate an azimuth control signal. The signal from the elevation pick-olf is transmitted through an amplifier 50 to control the follow-up support (not shown), upon which the gyro and pick-olf 46 are mounted. Such a support may carry the sight structure as indicated in the aforesaid Garbarini et al. patent, from which the elevation of the gun is controlled. Similarly, the output of the pick-olf 46 controls through amplier 59 a follow-up support in azimuth (not shown) which furnishes the base line for controlling the `gun in azimuth. Since this invention is concerned only with the gyroscope, further description of the over-all system need not be given.

It will also be understood that while I speak of rotation in azimuth of the sight and its connected parts, this term includes orientation in the slant plane of the sight or gun as well, since such a plane may be used as a reference instead of a truly horizontal plane.

vSince many changes could be made in the above oonstruction and many apparently widely different embodiments of this invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. In a device for applying controlled torques to a gyroscope about an axis thereof, a member, means pivotally mounting said member for rotation about an axis to one side of said gyro axis, a bell crank lever pivoted t-o Asaid member at a point remote from both of said axes, a link connecting one end of `said lever to the gyro by a pivot normally coaxial with said sec-ond axis, said link normally lying with its pivotal connection to said bell crank coaxial with said gyro axis, a tension spring connecting the other end of said lever and a point on said member, and means for displacing a point on lsaid member through a distance proportional to the desired torque.

2. A torquing device as claimed in claim 1l wherein the bell crank angle is such that the effective lever arm of the spring is increased at a rate matching the decrease in spring tension when the gyro departs from its normal position about the torque axis.

3. A torqu'ing device as claimed in claim 1 wherein said link has the same effective length as the distance between the said gyro axis and the pivot of said link to the gyro, whereby a `small shift in the position of the gyro about its said axis will not exert an effective torque on the gyro.

4. A spring biased lever system for applying a torque to a gyro about an axis of the gyro proportional to the extent of a displacement imparted to a point in the system, comprising a bell crank lever, a pivoted member on which said bell crank is pivoted, a biasing spring connecting said lever and member, a link connecting said bell crank and a point on the gyro below said axis such that in the zero position its point of connection to said bell crank lies coaxial with said first axis and is not displaced by tilt of the gyro and means for displacing said first named point in the system through a distance proportional to the desired torque to tilt said member without tilting said bell crank on said member.

5. A torqu'ing device as claimed in claim 4 wherein the bell crank angle is such that the effective lever arm of the spring is increased at a rate matching the decrease in spring tension when the gyro departs from its normal position about the torque axis.

References Cited by the Examiner UNITED STATES PATENTS 1,688,361 10/1928 Talbot 74-592 1,855,093 4/1932 Bruce et al 74-470 X 2,383,409 8/1945 Newell 74-5.4

MILTON KAUFMAN, Primary Examiner.

SAMUEL SPINTMAN, SAMUEL BOYD, Examiners.

T. W. SHEAR, A. M. HORTON, Assistant Examiners. 

4. A SPRING BIASED LEVER SYSTEM FOR APPLYING A TORQUE TO A GYRO ABOUT AN AXIS OF THE GYRO PROPORTIONAL TO THE EXTENT OF A DISPLACEMENT IMPARTED TO A POINT IN THE SYSTEM, COMPRISING A BELL CRANK LEVER, A PIVOTED MEMBER ON WHICH SAID BELL CRANK IS PIVOTED, A BISAING SPRING CONNECTING SAID LEVER AND MEMBER, A LINK CONNECTING SAID BELL CRANK AND A POINT ON THE GYRO BELOW SAID AXIS SUCH THAT IN THE ZERO POSITION ITS POINT OF CONNECTION TO SAID BELL CRANK LIES COAXIAL WITH SAID FIRST AXIS AND IS NOT DISPLACED BY TILT OF THE GYRO AND MEANS FOR DISPLACING SAID FIRST NAMED POINT IN THE SYSTEM THROUGH A DISTANCE PROPORTIONAL TO THE DESIRED TORQUE TO TILT SAID MEMBER WITHOUT TILTING SAID BELL CRANK ON SAID MEMBER. 